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The measurements of K-shell ionization cross sections for Fe, Ni, and Zn were performed using 7-29 keV electron impact on thick targets. Monte Carlo simulations were employed to correct the effects due to the multiple-scattered electrons and bremsstrahlung photons as well as other secondary particles within the thick targets. The so-called Tikhonov regularization method was adopted to deal with the ill-posed inverse problem involved in the thick-target method. The experimental results were compared with the DWBA and PWBA-C-Ex predictions as well as existing experimental data from the literature. It is observed that our experimental data are in better agreement with the theoretical results based on the DWBA model developed by Bote et al. Key words: ionization cross section, Monte Carlo simulation, thick targets. Nous mesurons des sections efficaces d'ionisation dans la couche K des elements Fe, Ni et Zn, generee par impact electronique aux energies 7-29 keV sur des cibles epaisses. Des simulations Monte Carlo sont utilisees pour corriger les effets de la diffusion multiple des electrons et des photons bremsstrahlung, ainsi que des particules secondaires dans la cible epaisse. Nous adoptons la methode de regularisation dite de Tikhonov pour tenir compte du probleme inverse mal-pose inherent a la methode de la cible epaisse. Nos resultats experimentaux sont compares avec les predictions de DWBA (approximation de Born d'ondes deformees) et PWBA-C-Ex (approximation de Born d'ondes planes avec correction de Coulomb et echange), ainsi qu'avec les donnees experimentales existant dans la litterature. Nous observons que nos resultats experimentaux sont en meilleur accord avec ceux du modele DWBA developpe par Bote et al. [Traduit par la Redaction] Mots-cles: section efficace d'ionisation, simulation Monte Carlo, cibles epaisses., 1. Introduction X-ray emission from solid samples exposed to electron beams in the low-energy region is the basis of some material analysis techniques, such as EPMA and AES methods, radiation [...]

Aims: To explore if and how symbiotic Phomopsis liquidambari‐rice system influences below‐ground straw decomposition and then nitrogen(N) transformation in response to environmental N levels. Methods and Results: Litter bag experiments were utilized to trace the decay process during rice growth phases (seedling (T1), tillering (T2), heading (T3) and maturing (T4) stage), with (E+) and without endophyte (E−), under low (LN), medium (MN) and high nitrogen (HN) supply. Litter, soil and plant samples were collected to evaluate the decay process, N transformations, plant quality and relative abundance of soil ammonia‐oxidizing archaea (AOA), ammonia‐oxidizing bacteria (AOB) and P. liquidambari. The results showed that straw decomposition increased by 19·76% (LN, T2 stage), 14·05% (MN, T3 stage) and 16·88% (MN, T4 stage) in E+ pots when compared with E− pots. Further analysis revealed that no significant endophyte × N interaction was found for straw decay rate and that the decay rate was reduced by a higher N supply (LN, 37·16 ± 0·65%; MN, 32·27 ± 1·72%; HN, 29·44 ± 1·22%) at the T1 stage, whereas straw decay rate and N release increased by 9·38 and 11·16%, respectively, mainly by endophyte colonization at the T4 stage. The abundance of AOA and AOB were altered, corresponding with the decay rate. Soil mineral N, straw mineral N and plant quality were shown to increase in E+ pots, depending on environmental N conditions and growth phase. The yield increased by 2·98% for E+ plants under MN level. Conclusions: Symbiotic P. liquidambari‐rice system promoted below‐ground straw decomposition and N transformation, depending on environmental N levels and plant growth phase. Significance and Impact of the Study: This study provides evidence that fungal endophyte–plant systems are able to promote N transformation by increasing straw decomposition. A reasonable combination of N inputs could enhance its advantage in agriculture ecosystems. [ABSTRACT FROM AUTHOR]

Aims: Plants, fungal endophytes (FEs) and the changing environment interact with each other forming an interlaced network. This study evaluates nonadditive and interactive effects of the FE Acremonium strictum and drought treatment on Atractylodes lancea plantlets. Methods and Results: By applying FEs (meristem cultures of At. lancea, fungal inoculation of Ac. strictum and plantlet acclimatization) and drought treatment (regular watering, mild drought, severe drought), a research system of At. lancea ramets under different treatments was established. During 12 days of drought treatment, the plantlets' physiological responses and basic growth traits were measured and analysed. Although drought and FE presence affected plantlet traits to differing degrees, the interactive effects of the two were more pronounced. In particular under mild drought treatment, the FE conferred drought tolerance to plantlets by enhancing leaf soluble sugars, proteins, proline and antioxidant enzyme activity; decreasing the degree of plasmalemma oxidation; and increasing the host's abscisic acid level and root:shoot ratio. When exposed to regular watering or severe drought, these effects were not significant. Conclusions: Plant traits plasticity was conferred by dual effects of drought stress and FEs, and these factors are interactive. Although FEs can help plants cope with drought stress, the beneficial effects are strictly constrained by drought degree. Significance and Impact of the Study: During finite environmental stress, FEs can benefit plants, and for this reason, they may alleviate the effects of climate change on plants. However, because the benefits of FEs are highly context dependent, the role of FEs in a changing background should be re-assessed. [ABSTRACT FROM AUTHOR]

Abstract: Thin films of Ni/Al2O3 cermet have been prepared by bias rf sputter deposition. A target composed of small Ni bars attached on Al2O3 plate (dia. 5 cm) was used as a sputter source. The sputtering was carried out in pure Ar gas. The resulted films were ceramic/metal composite consist of crystalline Ni metal gains and amorphous Al2O3 as characterized by X-ray diffraction and transmission electron microscope. Film morphology was observed by scanning electron microscope and was found to vary with applied bias. The films can be heated as a suitable current was applied, and the film resistance changed with film temperature. By measuring the resistance variation under different flow rates, the films can be used as flow sensors. The performances of the films deposited under different conditions were tested and compared. [Copyright &y& Elsevier]

Abstract: In this study, we investigated the photosynthetic physiological basis in 'PC' transgenic rice (Oryza sativa L.), showing high-level expression of the gene encoding C4 phosphoenolpyruvate carboxylase (pepc), by hydrogen peroxide (H2O2). The C4-PEPC gene (pepc) from maize in the transgenic rice plants was checked by PCR. Comparison of yield components and photosynthetic indices between PC and untransformed wild-type (WT) plants indicated that increased yield in PC was associated with higher net photosynthetic rate and higher activities of phosphoenolpyruvate carboxylase (PEPC). Both PC and WT plants were treated with 1 mmol L−1 abscisic acid (ABA), 0.04% 1-butanol (BA), 2 mmol L−1 neomycin (NS), or 2 mmol L−1 diphenyleneiodonium chloride (DPI) to investigate the relationship between photosynthesis and levels of H2O2 and phosphatidic acid. In both PC and WT, ABA induced H2O2 generation and simultaneous decrease in stomatal conductance (g s). PC plants treated with BA showed decreased H2O2 content and strongly increased g s within 2 h of treatment. Similar results were observed in response to DPI treatment in PC. However, WT did not observe the decrease of H2O2 during the treatments of BA and DPI. The reduced H2O2 content in PC caused by BA treatment differed to that induced by DPI because BA did not inhibit NADPH oxidase activities. While BA induced a larger PEPC activity in PC, and higher catalase activity as well. These results indicated that the regulation of endogenous H2O2 metabolism of PC could be helpful for enhancing photosynthetic capability. [Copyright &y& Elsevier]